Cartridge fuse

ABSTRACT

A cartridge fuse having an open ended sleeve type tubular body member with a removable terminal disc type plate disposed at each end thereof and supporting therebetween a replaceable solid fusible electrical conductive link adapted to melt at a given temperature to break an electrical circuit, the terminal plate being removably secured to the body member by a terminal cap threaded onto each end of the body member, and the body member being manufactured of a transparent polysulfone material having a dielectric constant of 3.14 at 60 Hertz, this providing a view of the internal fusible link from any angle through the body.

United States Patent m1 m1. 3,864,656 Labelle Feb. 4, 1975 CARTRIDGEFUSE Primary Examiner-J. D. Miller [76] Inventor: Bernard C. Labelle,324 Valley Exammer Fred Brook Dr., Lancaster, Pa. 17601 [22] Filed: Feb.19, 1974 AB TRACT [21] Appl. No.: 443,901 A cartridge fuse having anopen ended sleeve type tubular body member with a removable terminaldisc type plate disposed at each end thereof and supporting [3%]:J.S.1|l 337/206, 337/241, 337/265 therebetwccn a replaceable solidfusible electrical q 85/30 conductive link adapted to melt at a giventempera- 1 o 3 7/1 ture to break an electrical circuit, the terminalplate 337/251 265 being removably secured to the body member by a 56 Rfd terminal cap threaded onto each end of the body I 1 e "antes member,and the body member being manufactured of UNITED STATES PATENTS atransparent polysulfone material having a dielectric 1,478,!09 12/1923Ellison 337/241 X R Constant of 3.14 at 60 Hertz, this providing a viewof 1,857,096 5/l932 Glowacki 337/24] X R the internal fusible link fromany angle through the 3,340,430 9/l967 Jenkins 337/206 X R bgdy,3,394,334 7/l968 Wright et al 337/24l 3 Claims, 3 Drawing FiguresCARTRIDGE FUSE BACKGROUND OF THE INVENTION l. Field of the InventionThis invention relates generally to cartridge fuses and moreparticularly to a novel and improved cartridge fuse having a replaceablefusible link therein which melts when overheated to break an electricalcircuit and wherein the link is visible through a transparent bodymember for inspection thereof exteriorly of the fuse.

2. Description of the Prior Art It has been known in the prior art toprovide cartridge fuses of various sizes, capacities, andconfigurations, but all of such fuses suffer from the disadvantage of anindividual having to shake or otherwise handle or test the same todetermine the working operation thereof, with the individual not beingable to determine the actual condition of the fuse link inside the fuseto see if it has been partially damaged ude to electrical overloads orthe like during the use of the fuse and should thus be replaced toassure maximum fuse capacity. Among such prior art devices are those ofthe type generally illustrated in the US. patents of Sherwood No.3,365,559; Baumbach No. 3,377,448; Baird No. 3,601,737; and Kozacka No.3,529,270.

SUMMARY OF THE INVENTION The present invention recognizes thedeficiencies and disadvantages of presently available cartridge fusesand provides a novel solution thereto in the form of an improvedcartridge fuse having a transparent tubular body member manufactured ofpolysulfone material providing required insulating characteristics andproviding for clear visibility of the condition of the fuse link at alltimes both during storage and during actual electrical operation of thecartridge fuse.

It is a feature of the present invention to provide an improvedcartridge fuse which is relatively simple in its construction and whichtherefore may be readily manufactured at a relatively low cost and bysimple manufacturing methods.

A further feature of the present invention provides an improvedcartridge fuse which is possessed of few parts which are of a rugged anddurable construction and which therefore may be guaranteed by themanufacturer to withstand many years of intended usage providing for thereplacement of the fuse link in the fuse whenever required as determinedby a visible inspection thereof through the transparent walls of thebody member or by a break in the electrical circuit to which the fuse isconnected in series relationship.

Yet still a further feature of the present invention provides acartridge fuse adapted to readily replace cartridge fuses presentlyavailable to provide for an improved cartridge fuse to update equipmentand the like.

Yet still a further feature of the present invention provides animproved cartridge fuse which is easy to use and reliable and efficientin operation.

Other features and advantages of this invention will be apparent duringthe course of the following description.

Brief Description of the Drawings In the accompanying drawings forming apart of this specification, and in which like reference characters areemployed to designate like parts throughout the same:

FIG. I is a perspective view of the cartridge fuse of the presentinvention;

FIG. 2 is an exploded perspective view of the car tridge fuse of theinvention; and

FIG. 3 is a front elevational view of the cartridge fuse of theinvention.

Description of the Preferred Embodiment Referring now to the drawings indetail there is illustrated a preferred form of a cartridge fuseconstructed in accordance with the principles of the present inventionand designated generally in its entirety by the reference numeral 10 andwhich is comprised of a body member I l. a pair of terminal plates l2, areplaceable solid fusible electrical conductive link l3, and a pair ofterminal end caps 14.

The body member II is manufactured of an open ended sleeve type tubularhousing 21 having threads 22 disposed circumferally about the oppositeend thereof. The housing 21 is transparent and is manufactured of apolysulfone material having a dielectric constant of 3.l4 at 60 Hertz,this providing a novel use for this material as to having the desiredoptical characteristics to provide complete visibility therethrough in amanner to determine the condition of fuse link l3 at any time duringactual operation of the fuse 10, this material being non-breakable ascompared to the use of glass tubes and the like. This is a novel use ofpolysulfone material which is manufactured by Union Carbide Company asattested to by an investigation conducted by Underwriters Laboratories,Inc. under File No. 43933 at which time this material was approved foruse in the renewable cartridge fuse of the present invention.

The terminal plates l2 are each of an identical construction and are ofsubstantially flat disc shapes having a diameter greater than theinternal diameter of the sleeve 1] but less than the external diameterthereof so as to be engaged on opposite ends 23 and 24 of the bodymember, each of the plates provided with a slot 26 adapted to receiveopposite ends 3] of fuse link 13 therethrough which are then bent in anangle of approximately to overlie the outer surface of the associatedterminal plate.

The fusable electrlcal conductive link 13 is adapted to melt at a giventemperature to break an electrical circuit with such designcharacteristics thereof selected for the capacity of the circuit to beprotected as normally measured in amperes, the normal type of link beingas illustrated in the drawings and including a reduced cross-sectionalarea 32 which normally will vary depending upon the rating of the fuselink.

The terminal end caps I4 are each identical in construction and are of acylindrical configuration having side walls 4| and a back surface 42with an open front end 43 with there being an interior threaded bore 44opening out of the front end and adapted to be threadedly received onbody member threads 22 in a manner to capture an associated one ofterminal plates l2 intermediate an associated end 23, 24 of the bodymember and an interior surface of the terminal cap back end 42. Theterminal caps are of an electrically conductive metal material as arethe terminal plates 12 and thus provide terminals exterior of the bodymember for electrically connecting the fuse link l3 in seriesrelationship with an electrical circuit to be protected, this normallybeing accomplished by inserting the fuse between a pair of fuse holders45 (FIG. 3) which electrically contacts the terminal caps 14.

There is thus provided a novel use for the polysulfone material toprovide for a transparent housing of a renewable cartridge fuse in orderto provide for visibility of the fuse link interior of the body memberat any time desired by an individual without having to remove the fusefrom the circuit or having to de-energize the circuit which the fuse isprotecting. In this manner the condition of the fuse link may be readilyinspected at normal intervals and be replaced if such inspectionillustrates any damage or disfiguration thereto such as may beencountered due to brief overloads in the circuit and the like which arenot sufficient to melt the fuse link and break the electrical circuitbut which are sufficient to partially melt or damage the fuse link andthus affect its efficiency of operation.

It is to be understood that the form of this invention herewith shownand described is to be taken as a preferred example of the same. andthat this invention is not to be limited to the exact arrangement ofparts shown in the accompanying drawings or described in thisspecification as various changes in the details of construction as toshape, size. and arrangement of parts may be resorted to withoutdeparting from the spirit of the invention. the scope of the novelconcepts thereof, or the scope of the sub-joined claims.

Having thus described the invention. what is claimed l. A renewablecartridge link fuse comprising:

an open ended sleeve type substantially tubular body member oftransparent polysulfone material providing unobscured visibilitytherethrough;

a pair of substantially flat disc shaped terminal plate members eachhaving a slotted opening provided therein. each plate member having adiameter greater than the interior diameter of said body member and lessthan the exterior diameter of said body member. each plate memberadapted to restingly engage an associated end of said body memberconcentric with the axis of said body member;

a solid fusible electrical conductive link element adapted to melt at agiven temperature. each end of said link adapted to pass through anassociated slotted opening of an associated plate member and then bebent at an angle of about ninety degrees to overlie the exterior surfaceof said plate member. and

a pair of external electrical circuit connection means. each of saidmeans adapted to be mounted to an associated end of said body member andelectrically connect to said fusible link providing a series electricalcircuit through said fusible link element.

2. The renewable cartridge fuse as set forth in claim 1 wherein saidpolysulfone material has a dielectric constant of 3.14 at Hertz.

3. The renewable cartridge fuse as set forth in claim 2 wherein saidbody member is threaded at the opposite ends thereof about its exteriorcircumference. and wherein said external electrical circuit connectionmeans comprises cylindrical terminal end caps. each end cap havingcylindrical side walls. a closed back end. and an open front end. theinterior circumference of each of said end caps being threaded andadapted to threadedly engage associated ends of said body member tosecure said end caps thereto in a manner remov' ably retaining saidterminal plate to said body manner. i 1 i 1* i

1. A renewable cartridge link fuse comprising: an open ended sleeve typesubstantially tubular body member of transparent polysulfone materialproviding unobscured visibility therethrough; a pair of substantiallyflat disc shaped terminal plate members each having a slotted openingprovided therein, each plate member having a diameter greater than theinterior diameter of said body member and less than the exteriordiameter of said body member, each plate member adapted to restinglyengage an associated end of said body member concentric with the axis ofsaid body member; a solid fusible electrical conductive link elementadapted to melt at a given temperature, each end of said link adapted topass through an associated slotted opening of an associated plate memberand then be bent at an angle of about ninety degrees to overlie theexterior surface of said plate member; and a pair of external electricalcircuit connection means, each of said means adapted to be mounted to anassociated end of said body member and electrically connect to saidfusible link providing a series electrical circuit through said fusiblelink element.
 2. The renewable cartridge fuse as set forth in claim 1wherein said polysulfone material has a dielectric constant of 3.14 at60 Hertz.
 3. The renewable cartridge fuse as set forth in claim 2wherein said body member is threaded at the opposite ends thereof aboutits exterior circumference, and wherein said external electrical circuitconnection means comprises cylindrical terminal end caps, each end caphaving cylindrical side walls, a closed back end, and an open front end,the interior circumference of each of said end caps being threaded andadapted to threadedly engage associated ends of said body member tosecure said end caps thereto in a manner removably retaining saidterminal plate to said body manner.